Where Does Wastewater Go?

Every time you flush the toilet, take a shower, brush your teeth, do your laundry, or wash the dishes; this wastewater is collected and treated by the City's sewer system.

Our sewer system collects and treats sewage from homes and businesses, stormwater (rainwater) and street runoff into the drains. This is our City’s lifeline protecting public health and environmental quality. Nearly one million residents, businesses and visitors rely on our sewer system every day.

We own and operate about 1,900 miles of sewer mains and laterals right under the street. End to end, it would stretch from here to Colorado (and back) and over 300 miles are more than 100 years old! In the last few years, we have increased the routine replacement of the sewers from 4 to 15 miles per year.

To ensure that San Francisco continues to have a reliable and seismically safe sewer system, we are upgrading and modernizing our aging combined sewer system. These upgrades include standalone projects, as well as the regular ongoing maintenance and repair efforts by our crews throughout the year.

How much wastewater is treated every day?

Each non-rainy day more than 80 million gallons of wastewater is collected and transported to one of three treatment plants (Southeast, Oceanside, and NorthPoint), where harmful pollutants like human waste, oil and other pesticides are removed before reaching the San Francisco Bay and Pacific Ocean. (When it rains, our wastewater system collects and treats up to 500 million gallons a day).

In just six days, you could fill a football stadium from top to bottom with wastewater. Our system is hard at work everyday! 

Learn how the system is unique. Next: Our Combined Sewers